Apparatus and method for determining contact lenses

ABSTRACT

Apparatus and method for determining a prescription for contact lenses, comprising in cooperative combination a refractometer and a keratometer, both hooked up to a computer, comprising a program for processing the results obtained from said meters in any desired sequence, optionally supplemented with personal data and the results of a tono-meter and/or vertexmeter in optional sequence. The apparatus and method are also suitable for detecting any requirement for readjustment of the lenses after a period of time of use, comparing the new data with the data stored in the memory of the computer, and providing any readjustment required.

This application is a continuation of U.S. application Ser. No.07/973,433, filed Nov. 9, 1992, now abandoned, which is a continuationof U.S. application Ser. No. 07/446,851, filed Dec. 6, 1989, nowabandoned.

The invention relates to an apparatus and method for determining aprescription for contact lenses. Both soft and hard lenses are known,which may optionally be permeable. However, it was hitherto not possibleto determine the appropriate lens accurately by individuals withoutexpertise in the field of measuring and calculating prescription forlenses. The present invention provides a solution to this problem.

For determining a prescription contact lenses the present inventionprovides an apparatus and method wherein individuals without specialeducation other than operating the relevant apparatus, are able todetermine the appropriate prescription contact lenses. In determiningthe prescription for a lens, in the present case a contact lens, aconsiderable number of special circumstances may play a part indetermining the appropriate lens to be used. In that respect it can bementioned by way of example the history of the eye involved, includingpossible eye-operations, the possibility of allergies, any use ofmedicines, special conditions in the workplace, such as fumes,air-conditioning, chemicals and smoking, and any medical indicationwhich might prohibit the use of contact lenses. The environmentalconditions are of special importance for gas-permeable lenses. In orderto collect this information, a list of pertinent questions should befilled out by checking with the client. These data should be stored fordetermining what type of lens should be used.

The apparatus according to the invention comprises in cooperation arefractometer, a keratometer, a vertexmeter, (a meter for determiningthe strength of spectacle glasses) and a tono-meter for determining thepressure in an eye-ball. In addition a slit lamp can be used forobservation of the lens, conjuctiva and blood vessels in order to obtainpossible contra-incications. These measurements can be madeautomatically or manually. Hitherto the data thus obtained were used forcalculation of the prescription for the lens. According to the presentinvention the data from the instruments used are fed automatically intoa computer, wherein the data obtained, together with the specialinformation mentioned in the previous paragraph are combined forobtaining the appropriate details of the lens required.

The customary refractometers, keratometers, vertexmeters and tono-metersfor use in the present invention may optionally be provided with aprint-out feature for printed out the results of the measurement withthe specific meter. Hitherto they have not been used in other than amanual combination, that is, that the results are combined and pluggedinto a relevant formula. According to the present invention, all metersdesired are directly connected with a computer, thus avoiding the needof any expertise of the operator other than handling the apparatusinvolved. Thus the history of all clients can be entered in a simplemanner and without errors, as may occur in manual combination, with thepossibility of easy retrieval if required.

In addition, the invention provides a method for determining theappropriate lens for an eye, comprising measuring the eye with arefractometer, a keratometer and optionally a tono-meter, automaticallyfeeding the data of these meters into a computer programmed to plugthese data into an appropriate formula, preferably in combination withindividual data on history, environmental conditions and medicalindication, which may affect the selection of the type of Lens. Thus theclient will obtain an accurately calculated lens without any risk ofeither insufficient expertise or errors in carrying out the calculation,as the programme has been screened accurately.

The apparatus according to the invention not only allows carrying outthese measurements, but also takes into account deviations of the eyessuch as astigmatism and the like. In addition the apparatus is suitablefor taking into account any deviations of the eye resulting from use ofthe contact lens, such as deformation of the cornea, which may demandswitching from spheric lenses to toric, i.e. elliptic lenses and viceversa. Alternatively it may be found that special lenses are requiredwhich may be toric or which may require manual manufacture onprescription by an eye-doctor.

The FIGURE shows a schematic representation of a preferred embodiment ofthe invention.

The invention will now be illustrated by means of the preferredembodiment, without limiting the invention thereto. A questionaireshowing up on the computer 1 screen, with only yes or no asalternatives, is checked with the client, with the operator feeding therespective answers to the computer. Subsequently the client ispositioned in front of a refractometer 2 which is manipulated by theoperator until an optimal result is obtained as indicated by theapparatus. This result is again passed on to the computer. Then theclient is positioned in front of a keratometer 3 which is also hooked upto the computer, and again the operator will manipulate the meter untilthe curvature of the relevant eye is accurately measured, whereupon thisresult is fed to the computer. If desired the results of similarmeasurements with a tono-meter 5 and optionally a vertexmeter 4 may beused in any sequence. Subsequently the computer will, on appropriatecommand, pass on the outcome of the combined information to a printershowing the requirements for the lenses for the eyes concerned. On thebasis of that information the lenses can be taken from available shockor be made to measure as the outcome may require.

It will be obvious from the above example that the sequence in which thevarious operations are carried out is not obligatory and that actuallyany sequence is suitable, provided that the results of each measurementare passed on to the computer. In addition it should be observed thatthe basic programme could be complied with by using only therefractometer in combination with the keratometer, thus taking intoaccount the curvature of the eye in determining the ultimate shape ofthe lens. The vertexmeter is optional for the case where the client isstill undecided whether he will opt for lenses or may prefer glasses, orwhere the history of the client is contra-indicative with respect to theuse of lenses.

It should also be observed, that the above apparatus and method allowadjustments of the lenses if required by easy check-up of their effectson the eye, the basic advantage being that under all circumstancesindividuals without special education in the field can do the job, whilesimultaneously avoiding human errors as all processing of the resultsobtained is without human interference.

I claim:
 1. An apparatus for prescribing contact lenses, comprising: arefractometer for taking a first measurement of a patient's eye andproducing a first output signal representative thereof; a keratometerfor taking a second measurement of the patient's eye and producing asecond output signal representative thereof; means for inputtingpersonal data of the patient relevant to prescription of contact lenses;and processing means for processing said first output signal, saidsecond output signal, and said personal data to prescribe contactlenses.
 2. An apparatus for prescribing contact lenses as claimed inclaim 1, further comprising a tono-meter for taking a third measurementof the patient's eye and producing a third output signal representativethereof, wherein said processing means processes said third outputsignal.
 3. An apparatus for prescribing contact lenses as claimed inclaim 2, further comprising a vertexmeter for taking a fourthmeasurement of the patient's eye and producing a fourth output signalrepresentative thereof, wherein said processing means processes saidfourth output signal.
 4. An apparatus for prescribing contact lenses asclaimed in claim 1, further comprising a vertexmeter for taking a thirdmeasurement of the patient's eye and producing a third output signalrepresentative thereof, wherein said processing means processes saidthird output signal.
 5. A method for prescribing contact lenses using anapparatus comprising a refractometer, a keratometer, and an input deviceoperatively connected to a processing device, comprising the steps of:performing a first measurement of a patient's eye using therefractometer; performing a second measurement of the patient's eyeusing the keratometer; inputting personal data of the patient relevantto prescription of contact lenses; and processing the first measurement,the second measurement, and the personal data with the processing deviceto determine a prescription for contact lenses.
 6. A method forprescribing contact lenses as claimed in claim 5, further comprising thestep of performing a third measurement of the patient's eye using atono-meter.
 7. A method for prescribing contact lenses as claimed inclaim 6, further comprising the step of performing a fourth measurementof the patient's eye using a vertexmeter.
 8. A method for prescribingcontact lenses as claimed in claim 5, further comprising the step ofperforming a third measurement of the patient's eye using a vertexmeter.9. A method for prescribing contact lenses as claimed in claim 5,wherein said personal data includes information concerning the patient'smedical history.
 10. A method for prescribing contact lenses as claimedin claim 5, wherein said personal data includes information concerningthe patient's work environment.
 11. An apparatus for prescribing contactlenses, comprising: a first device for taking a first measurement of apatient's eye and producing a first output signal representativethereof; a second device for taking a second measurement of thepatient's eye and producing a second output signal representativethereof; means for inputting personal data of the patient relevant toprescription of contact lenses; and processing means for processing saidfirst output signal, said second output signal, and said personal datato prescribe contact lenses.
 12. An apparatus for prescribing contactlenses as claimed in claim 11 further comprising a third device fortaking a third measurement of the patient's eye and producing a thirdoutput signal representative thereof, wherein said processing meansprocesses said third output signal.
 13. An apparatus for prescribingcontact lenses is claimed in claim 12, further comprising a fourthdevice for taking a fourth measurement of the patient's eye andproducing a fourth output signal representative thereof, wherein saidprocessing means processes said fourth output signal.
 14. A method forprescribing contact lenses using an apparatus comprising the steps of:performing a first measurement of a patient's eye using a first device;performing a second measurement of the patient's eye using a seconddevice; inputting personal data of the patient relevant to prescriptionof contact lenses; and processing the first measurement, the secondmeasurement, and the personal data with a processing device to determinea prescription for contact lenses.
 15. A method for prescribing contactlenses as claimed in claim 14, further comprising the step of performinga third measurement of the patient's eye using a third device.
 16. Amethod for prescribing contact lenses as claimed in claim 15, furthercomprising the step of performing a fourth measurement of the patient'seye using a fourth device.
 17. A method for prescribing contact lensesas claimed in claim 14, wherein said personal data includes informationconcerning the patient's medical history.
 18. A method for prescribingcontact lenses as claimed in claim 14 wherein said personal dataincludes information concerning the patient's work environment.